Tuning indicator valve of small dimension and a high sensitivity



Jan. 21, 1958 F. MALSCH 2,820,916

TUNING INDICATOR VALVE OF SMALL DIMENSION AND A HIGH SENSITIVITY Filed Aug. 50; 1952 FIG. I. FIG. 3.

INVENTOR .F/P/EDEE/CH M41. 507

ATTORNEY United States Patefif TUNING INDICATOR VALVE OF SMALL DIMENSION AND A HIGH SENSITIVITY Friedrich Malseh, Esslingen-Waldenhronn, Germany, as-

signor to International Standard Electric Corporation, New York, N. Y., a corporation of Delaware Application August 30, 1952, Serial No. 307,188

Claims priority, application Germany September 5, 1951 4 Claims. (Cl. 313-1075) The present invention relates to voltage indicator valves such as are for example used in tuning, and referred to frequently as magic eye tubes. A voltage indicator valve has been proposed, as shown in the specification of my copending U. S. application Serial No. 294,938 filed June 21, 1952 for Tuning Indicator Valve, which relates to a tuning indicator valve in which a luminous screen is employed, the length of which is considerably longer than its Width. In such a device it is possible to design a voltage indicating valve with a small diameter cylinder, the indicating accuracy of which is just as good as one of valves having a larger diameter and a circular luminous screen. One example is described in said copending application in which two luminous sectors move symmetrically with respect to the plane of symmetry of the luminous screen as is also the case with the conventional magic fan type of magic tuning eye tube. This is attained by aligning the axes or symmetrical planes of the luminous screen, the gun system, and the deflecting system. With these valves the tuning sensitivity is determined by the path of the luminous point on the edge of the luminous screen. In accordance with the present invention this path and also the sensitivity of the latter described type of valve may be furthermore considerably increased by the fact, that the axis of the gun system and the deflecting system is twisted with respect to the axis or plane of the luminous screen, i. e. the axes or the symmetrical planes of the gun system and of the deflecting system form an angle with the axis or symmetrical plane of the luminous screen.

The above-mentioned and other features and objects of this invention and the manner of attaining them will become more apparent and the invention itself will be best understood, by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein:

Fig. 1 is a schematic plan view of the indicating system of a tube viewed in the direction 1-1 of Fig. 4 and Fig. 2 is a schematic diagram of a modification thereof in which the electrode system is partially covered.

Fig. 3 represents an embodiment having an asymmetrical gun system and deflecting system.

Fig. 4 represents an example for a complete valve partly in section along the line 4-4 of Fig. 1, and incorporating an indicator according to this invention and including the amplifier parts of the completed tube.

In Fig. 1 an example of the working assembly has been represented schematically. The gun system and the defleeting system comprises the cathode 1, the grid 2 surrounding the cathode and serving to generate a space charge and which, as a rule, is connected to the cathode, the electrodes 3 and 4, normally at luminous screen potential and serving to generate a strong electric deflecting field, the ring-shaped electrode 5 connected to the luminous screen and likewise lying on luminous screen potential, inducing the electric field in a way that the luminous screen is completely illuminated without stray e 2,820,916 Patented Jan. 21: 1958 electrons being able to fly over the edge of the luminous screen, and the deflecting electrode 6, the potential of which is variable, for instance, between the cathode and the luminous screen potential. The axis or plane of symmetry of this gun and deflecting system is twisted with respect to the axis of the luminous screen 20 through the angle a. Thus one of the shadow edges on the screen, when driven by a change of voltage at the deflecting electrode 6 through an angular variation 3, for instance 60, nearly sweeps the entire luminous screen 20, so that the terminal point of the luminous edge (the shadowedge) approximately moves from point 9 to point 10. The terminal point of the other shadow edge simultaneously moves approximately from point 11 to point 10. Thereby the shadow edge sweeps the angle '7. For adjusting the voltage maximum one only uses the movement of the one shadow edge from point 9 via the edge of the luminous screen to point 10. This path approximately is double the size produced by a symmetrical arrangement of the gun system and deflecting system and of the luminous screen. It is obvious, that this path 9-10 represents the greater part of the luminous screen circumference, Whereas the path ill-ll is very much smaller. As will be clear from reference to Fig. 4, the luminous screen 20, which also serves as an anode for the indicator, is dish-shaped and has a generally planar opening. The inner surface of this screen is coated with luminous material.

With the gun system and deflecting system as represented in Fig. 1 one obtains a deflecting angle 5 of approximately 60. If it is desired, therewith, to obtain the longest path 9-10, then the angular displacement, between the symmetrical planes, a must amount to about 30, viz. the angle is conveniently half as large as the angle ii. If one restricts oneself to reading the variation of the angle {3 and desists from an observation of the angle '7, then the gun system and the deflecting system can be made asymmetrical with respect to the plane 7 which heretofore has been designated as a symmetrical plane. Thus it is possible to arrange and to form the deflecting electrodes 4 and 6 still more favorably, so that an enlargement of the angle 5 on to and more will be possible. Thus the length of path from point 9 via the luminous screen circumference to point 10 will become somewhat longer.

In order to achieve a clear luminous picture, it may be convenient to cover that part of the luminous screen, which is not used for the purpose of tuning. Such a type of covering is represented at 13 in Fig. 2 and is shown shaded. The one shadow edge of the indicating beam 12-9 will then move to 12-10, whereas the path of the other shadow edge from 12-11 to 12-10 is nearly covered entirely and will only appear shortly before the complete disappearance of the shadow, which causes an increase of the reading sensitivity at a very small shadow angle.

Fig. 3 shows an embodiment in which the gun system and the deflecting system are asymmetrically disposed with respect to plane 7 which hitherto has been designated as a symmetrical plane. The designations correspond to those of Fig. 1. The electrode 4 is larger than electrode 3 and is, besides, arranged nearer to the cathode 1 and the deflecting electrode 6 than the electrode 3. Thereby a specially great deflecting angle a will be obtained, whereas the deflecting angle 'y is relatively small.

Fig. 4 illustrates an example of a valve incorporating a screen and electrode assembly as shown in the preceding figures. The beam generating and deflection system and the amplifier system use the common cathode 1. Grid 2, which is drawn above the cathode, belongs to the indicating system and controls the formation of a space charge around the cathode in a known manner. The deflecting V electrode 6 is connected to anode 16, of the amplifier system, which is drawn below the cathode. Grid 150i the amplifier system is locatedbetween cathode and anode 16. The pins in the stern press are denoted by 17. Electrodesi: and 4 areomitted the. interest ofi'clarity. Fig. 4 shows only some of these pins, which are connected'to the respective 'electrodesmas is schematically showre-in the conventional manner. The remaining lead-in wires and pins arev not represented in Fig. 4; The indicating and amplifier system is supported'by the l'ead inwi'res arranged between the electrodes and the pins; The arrangement of the entire system may be chosen with the cathode directed parallel or obliquely towards the stem press of the valve. This arrangement ofiers the advantage of enabling the use of an especially short cathode.

While I'have described above the. principles of; my invention in, connection with specific. apparatus, it is to be clearly understood that this; description; is made onlyby wayof example and'not as; alimitation to the scope of my invention'as'set forth. in the objects thereof and in the accompanying claims.

' What is claimed is:

1. An optical voltage indicating valve comprising a beam forming assembly; including an electron emitting source, a pair of deflecting electrodes on opposite sides of said source, anda deflecting control electrode, said conarsenals.

trol electrode and said source substantially defining a plane. of symmetry for saideassembly, .a. luminous screen positioned to receive electrons from said beam assembly,

having a dished surface with a substantially planar opening perpendicular to the axis of said source'and havinga plane of symmetry substantially through said control elec trode. said beam assembly eing mounte wi h sp n of symme ry a 'an angle. to the plane i symmetfryef id.

luminous screen.

2,. Optical voltagefiindicating valve. according-to ciaim 1, wherein said angle is approximately 30 3. An optical voltage indicating valve according to Claim whe in ai a g eis gr ter than 9 4. An optical voltage indicating valve according to claim 1:, wherein said angle is half thezutilizati'en agree: ray deflection.

References Cited in the file of this patent U ITE STATES PA'ITENIS 1 V q Aug-1.8; 119356 

